Multilayer optical films, which can provide desirable transmission and/or reflection properties at least partially by an arrangement of optically thin layers (“microlayers”) of differing refractive index, are known. It has long been known to make such multilayer optical films by depositing a sequence of inorganic materials in microlayers on a substrate in a vacuum chamber. Typically, the substrate is a relatively thick piece of glass, limited in size due to constraints on the vacuum chamber volume and/or the degree of uniformity possible by the deposition process.